Marco Denevi (May 12, 1922 in Sáenz Peña, Buenos Aires – December 12, 1998) was an Argentine award-winning author of novels and short stories, as well as a lawyer and journalist. His work is characterized by its originiality and depth, as well as a criticism of human incompetence. His first work, a mystery called Rosaura a las diez (1955), was a Kraft award winner and a bestseller. In 1964, it was translated into English as Rosa at Ten O'Clock. Other famous works of his include Los expedientes (1957), Ceremonia Secreta (1960), El cuarto de la noche (1962), and Falsificaciones (1966).

He is less known as an essayist, but he also cultivated this genre with his República de Trapalanda (1989), a late work, in which he takes on Ezequiel Martínez Estrada and Domingo Faustino Sarmiento's view of the Argentine republic.

He was born in the province of Buenos Aires, Argentina, and at a young age he began playing the piano and reading. He graduated from college in 1939, and did not receive his law degree until 1956.

In 1987 he was inducted into the Argentine Academy of Letters.